1. Field of the Invention
The present invention relates to flow meters, and more particularly to a combination flow meter and drip chamber used for measuring the flow rate of fluids parenterally administered to a patient.
2. The Prior Art
Intravenous infusion of fluids into a patient has long been a commonplace hospital procedure. Typically, intravenous infusion apparatus consists of an indwelling catheter that is connected through tubing to a fluid source such as an elevated plastic bag.
Because of the importance of knowing the exact amount of fluid being received intravenously by a patient, it is necessary to frequently monitor the flow rate of the infusion fluid. This is typically accomplished by the use of a drip chamber. A drip generating source in direct communication with the fluid source allows the fluid to be released as drops into a drip chamber. A predetermined volume per drop is determined by the size of the opening of the drip generator. Thus by counting the drops over a period of time one can calculate the flow rate using the predetermined volume per drop.
Drip chambers are advantageous because they provide a readily visible indication that fluid is flowing through the system to the patient. However, in the past, one of the problems associated with drip chambers has been the excessive time consumed in the procedure of counting the drops and calculating the flow rate. Not only is this procedure time consuming, but it is subject to human error in miscounting the drops or miscalculating the flow rate.
In some kinds of situations it is of utmost importance to provide a carefully controlled flow rate for the infusion fluid. For example, proper administration of some types of medication may require continuous infusion at carefully controlled flow rates over extended periods of time.
Thus, various types of metering devices have ben developed in order to avoid the potential for inaccuracy that is inherent with conventional type drip chambers, as described above. For example, see U.S. Pat. Nos. 4,043,322, 3,877,428, 3,807,389, 3,690,318 and 3,233,457.
Although these various types of metering devices may improve the safety and accuracy of metering parenterally administered fluids, they are much more complex and more expensive to build than conventional drip chambers. Moreover, many of them do not provide the type of easily visible inspection that is available with a drip chamber.
Thus, what is needed is a combination flow meter and drip chamber that is inexpensive and that eliminates the potential for inaccuracy of a conventional drip chamber and which still provides the same type of ready visibility as a drip chamber. Such an invention is illustrated and described herein.